1. Field of the Invention
The present invention relates to a unit for indicating lights and indicating lights installed at, for example, automated machine systems, production lines, parking lots and dangerous areas for indicating, based on a signal, various states such as shortage of a material, workpiece jam, a full state of the parking lot, a dangerous state and the like.
2. Description of Related Art
As a conventional indicating lights, there is known, for example, indicating lights including a plurality of units stacked on top of each other. The unit has a cylindrical case and a plate-like terminal extended along an axial direction of the case. Corresponding units are stacked with their corresponding terminals contacting each other to establish electrical connection and then, a long fixing screw is extended through these units for securing the corresponding units to each other (see, for example, JP-A-282605 and JP-A-2000-82846).
Unfortunately, the conventional indicating lights have the following drawback. When the long fixing screw is inserted through the units to assemble these, the stacked units, which are not yet connected with each other, need be held in place with hand. This leads to a cumbersome assembly step requiring time and labor.
As another conventional indicating lights, there is known an assembly including a unit having a cylindrical case and a linear terminal extended axially of the case and bent at one end thereof. The indicating lights are arranged such that the cases of corresponding units in stacked relation are rotated relative to each other thereby establishing connection therebetween while bringing their linear terminals into contact in a crossed manner (see, for example, U.S. Pat. No. 5,952,915).
However, this type of conventional indicating lights suffers unstable electrical connection because the pair of linear terminals of the pair of units connected with each other are brought into point contact.
An object of the invention is to provide a unit for indicating lights and indicating lights which can save labor for assembling the units and ensures the positive electrical connection between the units.
In accordance with a preferred embodiment of the invention for achieving the above object, a stackable unit for indicating lights comprises: a cylindrical case having first and second end portions; a pair of connection means disposed at the first and second end portions of the case, respectively, and each establishing connection with a corresponding end portion of a case of a corresponding unit via relative rotation of the cases; and an electrical connection member extended between the first and second end portions of the case for establishing electrical connection between units corresponding to each other, wherein the electrical connection member at least includes a plate member as a part thereof, wherein first and second ends of the electrical connection member are provided with first and second terminal portions, respectively, each terminal portion establishing connection with a corresponding terminal portion of a corresponding unit, and wherein at least one of the first and second terminal portions is provided at the plate member and includes a contact portion capable of resiliently establishing linear or face-to-face contact with a corresponding terminal portion of a corresponding unit.
According to the embodiment, when the indicating lights are assembled, a unit and a corresponding unit thereto can be readily connected with each other by stacking a case of the corresponding unit on that of the unit and then relatively rotating the cases to each other.